Self-assembling synthetic materials come together when tiny, uniform building blocks interact and form a structure; however, nature lets materials like proteins of varying size and shape assemble, allowing for complex architectures that can handle multiple tasks.
The behavior of microscale silver plates of varied size and nanoscale thickness in liquids was observed. Because the particles used in self-assembling materials are so small, they behave like atoms and molecules, which allows researchers to use classical chemistry and physics theories to understand their behavior.
The non-uniform particles repel and attract according to laws of nature in plain, deionized water; however, when salt is added to the water, changing electrostatic forces trigger a multistep assembly process. The non-uniform particles begin to assemble to form columns of stacked silver plates and further assemble into increasingly complex, ordered, 3D hexagonal lattices.
Particles can be seen assembling in this hierarchy using a light microscope. This enables tracking of particle motions one by one and studying the assembly dynamics in real time.
This work could enable development of reconfigurable self-assembly materials that can change from one type of solid crystal to another type with different properties for a variety of applications.